In accordance with technological developments, electronic devices (for example, smart phones) having a display screen are being developed to show images clearly at any view angle. The electronic devices provide users with the ability to identify images from a wider view angle. However, electronic devices providing a screen with a wide view angle may have a problem in protecting personal information in a public place. For example, when the electronic device is in a public place such as a subway, bus, and airport, personal information or security information can be exposed to neighboring persons because the screen has a wide view angle. In particular, in case of performing a banking-related function (for example, password input of internet banking and input of public authentication information) by using an electronic device, security measures are necessary for screens having a wide view angle. As electronic devices having a display are being used more frequently, the necessity of screen security for electronic devices is increasing.
As a method for limiting a view angle of a display, a security film can be attached to a display of an electronic device. The security film can be attached to an external side of the display of the electronic device, i.e., on a glass surface. The electronic device attached with a security film may have decreased clarity and view angle of the display. If the security film is attached to an electronic device once, it may be difficult to remove the security film. Although a user can select an appropriate security film for a security function, it may be difficult to remove the security film afterward. Further, because the attached security film limits a view angle in a basic direction, the view angle cannot be limited efficiently or the image quality can be depleted if a display direction of the electronic device (for example, a vertical or horizontal direction) changes.